Plant water relations 2

Question 1

osmoconditioning is commonly known as

Answer 1

osmopriming

Question 2

what are seeds treated with in osmo-priming?

Answer 2

a low water potential solution

Question 3

why does a low water potential solution allow the seeds to partially hydrate in osmopriming?

Answer 3

the low water potential penetrates the seed at a slow rate allowing the seed to start imbibition but stop before germination

Question 4

all seeds treated with osmopriming have a head start and therefore greater performance indicated by what 3 things

Answer 4

higher germination percentage, greater germination uniformity, and increased germination speed

Question 5

what is the mineral nutrient that causes lettuce tip-burn when deficient?

Answer 5

Ca 2+

Question 6

How does the environment play a role in causing the deficiency of Ca 2+ (lettuce) and that too particularly the inner leaves?

Answer 6

The boundary layer of the surrounding leaves buffers the small leaves in the center. Due to this transpiration is reduced in the inner leaves and since Ca is transported by transpirational pull it becomes deficient in the inner leaves.

Question 7

_____ ions are taken up by the ____ cells from the surrounding cells. This uptake of ions is facilitated by certain membrane transport proteins called _________, which are triggered by ____ light.

Answer 7

K+; guard; proton pumps; blue

Question 8

Such uptake of ions by these cells lead to the ______ of water potential in these cells compared to the surroundings.

Answer 8

decrease

Question 9

Consequently, ______ moves into these cells from the surrounding cells resulting in the _____ and the opening of stomata.

Answer 9

water; radial expansion of the guard cells

Question 10

Define boundary layer

Answer 10

Layer of undisturbed air on the surface of a leaf

Question 11

how does boundary layer influence rate of transpiration?

Answer 11

it increases transpiration most of the time

Question 12

list 3 plant related factors that help reduce the transpirational water loss by influencing the boundary layer

Answer 12

thermonasty, trichomes, and sunken stomata

Question 13

how does sunken stomata help reduce the transpirational water loss by influencing boundary layer?

Answer 13

the more humid boundary layer around the sunken stomata is not easily blown away by the wind

Question 14

how do trichomes help reduce the transpirational water loss by influencing boundary layer?

Answer 14

they create a boundary layer which reduces transpiration

Question 15

how does thermonasty help reduce the transpirational water loss by influencing boundary layer?

Answer 15

because when the leaves curl the boundary layers will overlap and it will be thicker

Question 16

give 2 reasons the rate of transpiration decreases at relatively high leaf temperatures

Answer 16

1. the plant has enough CO2 for photosynthesis so there is no need for stomata to remain open and they close 2. The rate of transpiration exceeds the rate plants can take up water and stomata close for survival.

Question 17

2 distinct roles transpiration plays in plant life

Answer 17

major driving force for water uptake in the plant and evaporative cooling for the plant